Userscript to restyle the Redmine 3.x default theme

redmine3.user.js

// ==UserScript==
// @name           Redmine 3.x Styler
// @namespace      created by Naga Puttagunta
// @description    Redmine 3.x Style Overrides
// @match 		   https://*/redmine/*
// @match 		   http://*/redmine/*
// @version        1.0
// ==/UserScript==

function addGlobalStyle(css) {
    var head, style;
    head = document.getElementsByTagName('head').item(0);
    if (!head) { return; }
    style = document.createElement('style');
    style.type = 'text/css';
    style.innerHTML = css;
    head.appendChild(style);
}

addGlobalStyle('.select2-results__option { padding: 0px ! important; }');
addGlobalStyle('.select2-results>.select2-results__options { max-height: 300px ! important ; }');